Nu-trifluoromethylamines and process for their production



United States Patent Ofi 3,355,454 Patented Nov. 28, 1967 ice 3,355,454N-TRIFLUOROME'IHYLAMTNES AND PROCESS FDR THEIR PRGDUCTION Erich Klauke,Cologne-Flittard, and Engelbert Kiihle, Cologne-Starnmheim, Germany,assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverknsen,Germany, a corporation of Germany No Drawing. ()riginal application Apr.23, 1963, Ser. No. 274,916. Divided and this application Sept. 28, 1965,Ser. No. 491,015 Claims priority, application Germany, May 15, 1962,

F 36,896 6 Claims. (Cl. 260249.5)

The present invention is a divisional application of US. patentapplication, Ser. No. 274,916, filed April 23, 1963, now abandoned, andrelates to novel N-trifluoromethylamines which have marked fungicidaland herbicidal properties, as well as a process for their production.

Few N-trifiuorornethylamines are known from the literature. Twocompounds from the aromatic series have been described. K. A. Petrov andA. A. Neimysheva (Z. Obsc. Chirn. 29, 2169 (1959)) obtainedN-trifiuoromethyl-aniline and p-N-trifluoromethyl-toluidine by thereaction of the corresponding isocyanide-dichlorides with anhydroushydrofluoric acid in an organic solvent. According to the statements bythese authors, the choice of the employed organic solvent is of decisivesignificance during this operation. Thus, the production ofN-trifluoro-.

methylamine can only be achieved in ether. In the presence of ethylchloride or in the absence of a solvent, polymericisocyanide-dilfuorides are isolated as the main product of the reaction.The Che rical structure of these polymeric reaction products is notspecified.

It is an object of the present invention to make available novelN-trifluoromethylamines. It is a further object of the invention todisclose a process for the production of the novelN-trifluoromethylamines. Moreover, it is also an objectof the inventionto provide novel materials which can be employed for the control offungi and weeds by virtue of their fungicidal and herbicidal properties.Further objects are indicated by the following decsription and theexamples.

It has been found that the novel N-trifiuoromethylamines of the formulawherein Ar represent an aromatic, carbocyclic, heterocyclic, orcondensed radical, optionally substituted by alkyl, alkoxy, and/or'acyloxy, which is substituted by at least one of the followingsubstituents halogen, nitro, nitrile, trifluoromethyl, COX, and SO X,where X represents halogen, alkoxy, alkyl, or aryl, and n stands for lor 2, have fungicidal and herbicidahproperties.

-It has further been found that the N-trifluoromethylamines of Formula Iare obtained when isocyanide-dichlorides of the formula wherein Ar and'nhave the same significance as in Formula I, are reacted with an excessof anhydrous hydrofluoric acid. 1

During the process according to the invention, the use of an organicsolvent may be dispensed with, and this constitutes a considerablesimplification of the reaction and of working up, particularly sincesolvents such as ether form stable oxonium salts with hydrofluoric acidwhich can be distilled.

The starting materials which can be employed for the process according.to the invention are plainly characterised by the above stated FormulaiI. In this formula, Ar preferably represents aromatic radicals with upto 10 carbon atoms, carbocyclic radicals with 5-6 ring members,heterocyclic radicals with 5-6 ring members, and condensed radicals suchas benzophenone, for example. These radicals represented by Ar may besubstituted by one of the following substituents: halogen such aschlorine, bromine or fluorine; nitro, nitrilo, trifluoromethyl, as wellas the COX and -SO X radicals wherein X preferably represents halogensuch as chlorine, bromine, and fluorine, alkoxy groups with 1-4 carbonatoms, alkyl groups with 1-4 carbon atoms, or phenyl. In addition to thesubstituents mentioned above, the groups represented by Ar may also besubstituted by alkyl, alkoxy, and/or acyloxy groups each with 1-4 carbonatoms.

The isocyanide-dichloride required as the starting materials forobtaining the products of the process accordin to the invention may beprepared by different methods, for instance by the chlorination ofisothiocyanates (Ber. 7, page 1228), by the chlorination ofN-arylformamides in thionyl chloride (German Patent No. 1,094,737), orby the chlorinationof dialkyl-anilines at an elevated temperature.

Isocyanidedichlorideswhich are prepared according to the above mentionedprocesses and are suitable for the reaction with anhydrous hydrofluoricacid are, for instance: I

4- chlorophenyl isocyanide-dichloride; 2,5dichlorophenyl-isocyanide-dichloride; 2,4,6trichlorophenyl-isocyanidedichloride;pentachlorophenyl-isocyanide-dichloride; 2,4-dichloroS-methylphenyl-isocyanidedichloride; Z-methyl5nitrophenyl-isocyanide-dichloride; 2-chloro-S-trifluoromethylphenyl-isocyauide-dichloride; 4-c arboxy methylphenylisocyanide-dichloride; 3-cyano-phenyl-isocyanide-dichloride;diphenylsulphone Z-isocyanide dichloride; 4-benzophenoneisocyanide-dichloride; 4-benzoyl chloride-isocyanide-dichloride; and thelike.

The term anhydrous hydrofluoric acid as employed for the reaction refersto the normal commercial product with a percentage content of 98100%.

The reaction is conveniently carried out so that the excess of anhydroushydrofluoric acid is first introduced and the isocyanide-dichloride isadded dropwise to it at temperatures between 10 and +20 C. However, theorder of addition may also be reversed, and this is always to berecommended when the starting material is a solid at room temperature.The progress of the reactio which is usually very fast, is readilyindicated by the liberated tion to the employed amount ofisocyanideichloride, and the end point of the reaction can easily berecognized by the cessation of the evolution of HCl. After the excess ofhydrofluoric acid has been expelled, working up of the reaction mixtureis carried out by distillation of the residue or by recrystallisation.In most cases, however, the crude product is sulficiently pure and canbe employed for subsequent reactions without further purification.

The compounds according to the invention possess herbicidal andfungicidal properties, and can therefore be employed for the destructionof weeds as well as for the control of fungi, particularly ofphytopathogenic, Woodrotting, and wood-discolouring fungi.

activity against wood-rotting, blue-rot, and also wooddiscolouringfungi.

The tests are carried out by the usual method. Compositions of theactive agents are prepared at different 4 vigorous evolution of HClensues, which subsides after 75 minutes. After the excess of HF has beendistilled off, 108 parts (98.2% of the theoretical yield) ofN-trifluoromethyl-2-methyl-5-nitraniline are isolated in the form ofconcentrations by taking up the active agent in about 4 5 yellowcrystals of MP. 81-83" C. M.P. 86-87" C. after times its weight ofdimethylforrnamide, adding some recrystallising once from benzene.poly-hydroxyethylene-benzyl ether as emulsifying agent, EXAMPLE 3 anddiluting this concentrate to the desired concentrations 7 I with Water.The compositions are added to a culture rne- N H dium (malt/agar-agar).The culture medium is then in- 10 oculated with the test fungi. Fourweeks after the 3 inoculation, the concentration at which fungus growthstill just takes place and the concentration at which this 0 growth iscompletely inhibited are determined. These coni.

centrations are referred to as inhibition indices and are stated in thetwo following tables for a large number of fungi. The statements ofconcentration relate to the percentage by weight of active agentreferred to the composition.

82 parts (0.33 mole) of2,4-dichloro-sym-triazinylisocyanide-dichloride-6 (=tetrameric cyanogenchloride) are added dropwise to 100 parts by volume of previouslyintroduced anhydrous hydrofluoric acid in an apparatus INHIBITIONINDICES AGAINST WOOD-ROT'IING FUNGI INHIBITION INDIOES Ophzostoma picea0. 04-0. 2 0. 04-0. 1 Scopularia phycomyc 0.04 0.2 0. 04-0. 1Trichosporium tingens- 0. 04-0. 2 0. 01-0. 04 Pullularia pullultms 0.04-0. 2 0. 1-0. 4 Endoconiophom coerulescem 0. 04-0. 2 0. 1-0. 4Ophiostoma pim' 0. 04-0. 2 0. 04-0. 1

The following examples are given for the purpose of illustrating theinvention. The term parts refers to parts by weight.

like that in Example 1. An intensive development of HCl starts at atemperature of about 10 C., which subsides only slowly since thechlorine atoms present at the 2- EXAMPLE 1 and 4-positions are exchangedduring a second stage. The

A5 reaction is allowed to continue for 17 hours'at a tempera- H turebetween 15 and 20 C., the excess of hydrofluoric 140 parts by volume ofanhydrous hydrofluoric acid are first introduced into a copper vessel,cooled with brine and fitted with stirrer, reflux condenser andthermometer, and cooled down to -2 C. 417 parts of4-chlorophenylisocyanide-dichloride are then run into this during theacid is then distilled off, and 62 parts (93.2% of the theoreticalyield) of 2,4-difluoro-sym-triazinyl-6 trifluoromethylamine are obtainedas the residue. The crude product can be distilled. Boiling point 80-83C./ 20 mm. Hg, M.P. 53-55 C.

The following compounds'were prepared by a method similar to that in thegiven examples:

course of minutes. A slow evolution of HCl ensues CF: CF: shortly afterthe start of the addition, which rapidly 1 1 intensifies and whichceases 15 minutes after the addition I has been completed. The excess ofHP is evaporated in 81 vacuo at 20 C. and the residue is distilled. 293parts (=75 of the theoretical yield) of N-trifluoromethyl-4- C1chloro-aniliue of RP. 85 C./ 13 mm. Hg are obtained, with 11 1.4920. 01

EXAMPLE 2 B.P.: 88 C./15 mm. Hg B.P.: 94-96" C./20 mm. Hg CF: CF3 CH3 II 1 NH NH N-CF3 I I Cl- C1 C1 N02 0 CH 116.5 parts (0.5 mole) ofZ-methyl-S-nitrophenyl-' 1 C1 isocyanide-dichloride of M.P. 59 C. arefirst introduced into the apparatus described above. 120 parts by volume90.9? Q/5 m Hg 1 mun-Hg of anhydrous HF are added thereto within 2minutes. A 75 MP4 3 1 DIIH NH C F N 01 B.P.: 6264 C./12 mm. Hg M.P.: 89.5 0.

(BF; (FF! 17111 NE l NO:

M.P.: 105107 C. M.P.: 8687 C.

i NH

1 C O O C M.P.: 118-120 C.

We claim: 1. A process for producing N-trifluoromethylamines whichcomprises contacting isocyanate-dichlorides of the formula \CI n with atleast a reactive amount of anhydrous hydrofluoric acid in the absence ofan organic solvent, to obtain a product having the formula wherein Ar isa triazinyl, an aromatic nucleus having up to carbon atoms and asubstituted aromatic nucleus having as substituent group a memberselected from the group consisting of chloro, methyl, nitro,trifluoromethyl, carboxymethyl, cyano, and

cyanate dichloride reactant is a member selected from the groupconsisting of 4-chlorophenyl-isocyanide-dichloride;

comprising admixing 4-chlorophenyl-isocyanide-dichloride with anhydroushydrofluoric acid at a temperature of about -2 C., the ratio ofisocyanide dichloride reactant to hydrofluoric acid being about 3:1 inparts by weight, and thereafter recovering the resulting product.

5. A process for producing a compound of the formula comprising slowlyadding anhydrous hydrofluoric acid toZ-methyl-S-nitrophenyl-isocyanide-dichloride at a tem perature of about2 C., the ratio of reactants being about 1:1 in parts by weight, andthereafter recovering the resulting product.

6. A process for producing a compound of the formula comprising slowlyadding 2,4-dichloro-sym.-triazinyl-isocyanide-dichloride-6 to anhydroushydrofluoric acid, the ratio of reactants being about 8:10 parts byweight, maintaining a temperature of about 10 C.20 C., and thereafterrecovering the resulting product.

References Cited UNITED STATES PATENTS 3,122,542 2/1964 Knusli et a1.260--249.5 X 3,137,694 6/1964 Riethmannetal. 260249.5

OTHER REFERENCES Petrov et a1. Chemical Abstracts, 1960, volume 54,pages 10911 to 10912.

WALTER A. MODANCE, Primary Examiner.

CHARLES B. PARKER, Examiner.

D. R. MAHANAND, I. M. FORD, Assistant Examiners.

1. A PROCESS FOR PRODUCING N-TRIFLUOROMETHYLAMINES WHICH COMPRISESCONTACTING ISOCYANATE-DICHLORIDES OF THE FORMULA